Students use their books to protect their heads during a earthquake drill inside a ground of the Paranaque National High School in Baclaran, Paranaque city, metro Manila February 22, 2011. A mild quake, recorded at magnitude 4.7 with a depth of 116km (72 miles) northwest of Batangas shook the Philippine capital Manila on Tuesday but did not cause any damage, a Philippines Institute of Volcanology and Seismology (PHILVOCS) official reported. The quake struck at 10.10 am (0210 GMT). Twenty minute
